bootstrap comparison failure with bootstrap-lto

[Matt]

On Fri, 18 Nov 2011, Ian Lance Taylor wrote:

> Matt <matt@use.net> writes:
>
>> Do I need to run a complete build first? When I run that make target
>> right after configure, it fails in multiple ways when building from
>> r181491:
>
> Hmmmm, you're right, it doesn't work.  Sounds like a bug.  Try running
> "make all-stage1" (I had to run it a couple of times for some reason)
> and then run "make configure-stage2-gcc" (which I also had to run
> twice).  You should wind up with a prev-gcc directory and a gcc
> directory.  The gcc directory is what will in the end become stage2-gcc.

Should I file a bug about the multiple runs being necessary? I poked 
around a bit and it seemed that different -j options results in a 
different number of tries. That being said, even -j1 required multiple 
tries. (This may be a symptom of one of the issues that causes my builds 
to fail spectacularly every blue moon when doing -jN>6.)

Beyond that, I now have the binary generated by prev-gcc/xgcc and it does 
indeed crash:

Starting program: /home/matt/src/gcc-trunk/obj/conftest

Program received signal SIGABRT, Aborted.
0x00007ffff7a733a5 in __GI_raise (sig=6) at 
../nptl/sysdeps/unix/sysv/linux/raise.c:64
64	../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or 
directory.
 	in ../nptl/sysdeps/unix/sysv/linux/raise.c
(gdb) bt
#0  0x00007ffff7a733a5 in __GI_raise (sig=6) at 
../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1  0x00007ffff7a76b0b in __GI_abort () at abort.c:92
#2  0x00000000004003c9 in main () at /tmp/conf.c:270


Is it tripping over a bug in the system compiler (again, GCC 4.6.1-based 
default from Ubuntu 11.10)?

Let me know how you'd like me to proceed.

Thanks!



--
tangled strands of DNA explain the way that I behave.
http://www.clock.org/~matt